Crystals, Super Magnets in Drug Discovery

Microscopic crystals could soon be zipping drugs around your body, taking them to diseased organs.

In the past, this was thought to be impossible – the crystals, which have special magnetic properties, were so small that scientists could not control their movement. But now a team of Chinese researchers has found the solution, and opened new applications that use these crystals to save lives.

If some magnetic materials, such as iron oxides, are small enough – perhaps a few millionths of a millimetre across, smaller than most viruses – they have an unusual property: their magnetisation randomly flips as the temperature changes.

By applying a magnetic field to these crystals, scientists can make them almost as strongly magnetic as ordinary fridge magnets. It might seem odd, but this is the strongest type of magnetism known. This phenomenon is called superparamagnetism.

Superparamagnetic particles could be ideal for drug delivery, as they can be directed to a tumour simply by using a magnetic field. Their tiny size, however, has made them difficult to guide precisely. Until now. Kezheng Chen and Ji Ma from Quingdou University of Science and Technology, Quingdou, China have demonstrated a method of producing much larger superparamagnetic crystals and have recently published their findings in Physics Letters A.

These large crystals do not show the unwanted magnetic properties of the small crystals. “The largest superparamagnetic materials that we have been able to make before now were clusters of nanocrystals that were together about a thousand times smaller than these,” says Chen. The large crystals are about the width of a human hair.

This discovery paves the way for superparamagnetic bulk materials that could revolutionise drug delivery in the body. And this is just the beginning. Chen's crystals might, for example, be useful in the many engineering projects that need "smart fluids" to build safer car parts or better human prostheses.

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Story from Elsevier. Please note: The content above may have been edited to ensure it is in keeping with Technology Networks’ style and length guidelines.

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